The present invention relates to injection molding and in particular to an improved mold and method for molding hinged articles.
In the conventional molding of hinged articles such as door and cabinet hinges, container-lid combinations and the like, the hinged sections are individually formed with loops or knuckles provided at an edge which cooperate with a separate pin in defining the hinge. Small plastic box components are sometimes formed with spaced spherical balls at an edge. When a similar ball on a mating component is snapped between the spaced balls a hinge is defined. In still another construction one hinged member is molded with a hook at an edge and the other is molded with an eye. The engagement of the hook and eye define yet another type of hinge.
In each of the prior art production methods the hinged components must be individually formed and then manually assembled. Assembly is a costly operation because of the labor involved. In addition, where plastic parts are designed to be snap fit with each other a certain amount of breakage inevitably occurs during assembly.
In view of the above, it is the principle object of the present invention to provide an improved mold and improved molding technique which permits the molding of hinged articles wherein the hinged components emerge from the mold already interengaged.
A further object is to provide such a mold and molding technique wherein the hinged components may be formed, within limits, of different plastic materials.
A still further object is to provide such a mold and molding technique which may be used with conventional injection molding equipment.
Still other objects and advantages will become apparent from the following description of the invention.